GELE Surveying (Geomatics) — Horizontal Curves (Simple, Compound, Reverse)Concept Map
Concept mapping is a retrieval-practice technique that works especially well on wide chapters like Horizontal Curves (Simple, Compound, Reverse). When Professional Regulation Commission (PRC) — Board of Geodetic Engineering writes a GELE Surveying (Geomatics) item that mixes two sub-topics, a concept-mapped reviewer sees the intersection in seconds. This page provides that map for Horizontal Curves (Simple, Compound, Reverse).
Exam context
On the GELE 2026, the Surveying (Geomatics) subtest carries a "Core" weight in Professional Regulation Commission (PRC) — Board of Geodetic Engineering's pattern. Horizontal Curves (Simple, Compound, Reverse) lands at position 5th out of 9 in the standard review order. Target score is 70% weighted average, no sub-test below 50%, and roughly a meaningful share of items come from Surveying (Geomatics) on a typical GELE paper.
Horizontal Curves (Simple, Compound, Reverse) - Concept Map
Central Concept
Horizontal Curves in Road & Rail Alignment Design
Related Concepts
Concept
Simple Circular Curve
Sub Concepts
- Curve Geometry & Elements
- Radius & Deflection Angle
- Degree of Curve
- Stationing System
Relationship To Central
Fundamental element; connects two tangent lines with constant radius
Concept
Curve Elements & Formulas
Sub Concepts
- Tangent Distance (T)
- Length of Curve (Lc)
- Long Chord (LC)
- External Distance (E)
- Middle Ordinate (M)
Relationship To Central
Define physical dimensions and positions of curve features
Concept
Degree of Curve
Sub Concepts
- Arc Definition (20 m standard)
- Chord Definition
- Radius Calculation
- Curvature Comparison
Relationship To Central
Specifies sharpness; inverse relationship with radius
Concept
Stationing & Layout
Sub Concepts
- Point of Curvature (PC)
- Point of Intersection (PI)
- Point of Tangency (PT)
- Station Calculations
- Field Marking
Relationship To Central
Locates curve features along route; essential for construction
Concept
Compound Curves
Sub Concepts
- Definition & Purpose
- Common Tangent Point
- Radius Combination
- Design Constraints
Relationship To Central
Two simple curves in same direction; handles complex terrain
Concept
Reverse Curves
Sub Concepts
- Definition & S-Curve Geometry
- Superelevation Runoff
- Tangent Requirements
- Safety Considerations
Relationship To Central
Two curves in opposite directions (S-shape); spiral transition needed
Concept
Practical Applications
Sub Concepts
- Highway Design Standards
- Railway Alignment
- Urban Road Networks
- Safety & Comfort
Relationship To Central
Real-world road & rail design scenarios
Concept
Common Errors & Verification
Sub Concepts
- PT Stationing Mistakes
- Degree Definition Confusion
- Angle Unit Conversion
- Formula Selection
Relationship To Central
Quality control in calculations and field work
Concept Connections
To
Curve Elements & Formulas
From
Simple Circular Curve
Strength
strong
Relationship
Formulas define all geometric properties of a simple curve
To
Radius & Sharpness
From
Degree of Curve
Strength
strong
Relationship
D is the measure of curvature; inversely proportional to R
To
Stationing & Layout
From
Tangent Distance (T)
Strength
strong
Relationship
T is used to calculate PC station from PI
To
Stationing & Layout
From
Length of Curve (Lc)
Strength
strong
Relationship
Lc is added to Sta PC to find Sta PT
To
Compound Curves
From
Simple Circular Curve
Strength
strong
Relationship
Compound curves are combinations of two simple curves with different radii
To
Reverse Curves
From
Simple Circular Curve
Strength
strong
Relationship
Reverse curves are two simple curves in opposite directions
To
Stationing & Layout
From
Curve Elements & Formulas
Strength
strong
Relationship
All calculated elements are used to determine station positions
To
Curve Elements & Formulas
From
Degree of Curve
Strength
moderate
Relationship
D values affect the selection of R, which affects all element calculations
To
Curve Elements & Formulas
From
Compound Curves
Strength
moderate
Relationship
Each curve in a compound uses the same formulas independently
To
Superelevation Runoff
From
Reverse Curves
Strength
strong
Relationship
Reverse curves require tangent segments for safe superelevation transitions
To
Practical Applications
From
Stationing & Layout
Strength
strong
Relationship
Correct stationing enables accurate field construction and layout
To
Stationing & Layout
From
Common Errors & Verification
Strength
strong
Relationship
Most common errors occur in stationing calculations; verification prevents them
To
Practical Applications
From
External Distance (E)
Strength
moderate
Relationship
E determines clearance requirements for buildings and obstacles
To
Curve Elements & Formulas
From
Middle Ordinate (M)
Strength
moderate
Relationship
M provides midpoint verification for curve shape accuracy
To
Stationing & Layout
From
Long Chord (LC)
Strength
moderate
Relationship
LC is used in chord surveys to verify curve geometry in the field
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